Figure 12.

Proposed model for EWcp as an integrator of multimodal signals and modulator of sympathetic output to multiple effector organs to maintain energy homeostasis in rodents under different conditions. Brain regions and effector organs are color coded by the main function with which they are involved. Brain regions that are implicated in two functions are depicted by two colors. Similarly, effector organs involved in two functions are noted in large fonts for main functions and in smaller fonts for secondary roles. Arrow thickness represents projection density based on literature. Dashed lines (with question marks) represent hypothetical pathways based on neuroanatomical data, but without physiological information yet to support their role in the EWcp circuit. For example, the effect of Ucn-1 from EWcp in PVN could occur directly or via presynaptic activation of CRF-R2 on NPY terminals from Arc. In addition, it is unknown if this effect of Ucn-1 in PVN might affect the activity of presympathetic neurons known to project directly to SPNs in the spinal cord. The direct projection from EWcp to the spinal cord (to SPNs or interneurons) has been reported in classical tracing studies; nevertheless, transneuronal retrograde tracing with PRV does not support this direct projection (or if it exists, it is very sparse). For clarity purpose, the figure only includes relevant neuroanatomical connections from/to EWcp in the brain, excluding most connections among other brain regions. Abbreviations: GI, gastrointestinal; IN, interneurons; LPB, lateral parabrachial nucleus; LPGi, lateral paragigantocellular nucleus; POA, preoptic area; SPoN, sympathetic postganglionic neurons. For the rest of the terms, see the list of abbreviations.